Glycosaminoglycans including heparin, heparan sulfate, chondroitin sulfate, dermatan sulfate and hyaluronic acid were analyzed by reversed polarity capillary electrophoresis. Detection was achieved at 240 nm based on the formation of a copper (II) complex in copper sulfate solution at low pH. Glycosaminoglycans having a high ratio of iduronic acid to glucuronic acid, as well as ones having lower molecular weight, gave the highest detection sensitivity using this method. Detection of the copper (II)-heparin complex is extremely sensitive, permitting the analysis of as little as 10(-9) g. This method was also successfully applied to the analysis of heparin oligosaccharides that lacked a chromophore prepared from heparin using controlled, low pH nitrous acid depolymerization.